Natural and human-induced erosion: combining short-term event-based research and landscape evolution modeling - A research set-up -

In many erosion studies, the assumption is made that all observed erosion features are the direct and indirect results of human actions. In geosciences, however, erosion is viewed upon as a natural denudational process. Consequently, in erosion research, spatial and temporal scales as well as research methods differ. On the one hand, plot-slope-small catchment scale, event based change, `human¿ timescales and field experiments are assessed. On the other hand, landscape regional scale, decadal change, timescales of landscape evolution (Quaternary) and landscape evolution models as tools are used. In the current research we aim to bridge the gap between these contrasting approaches. By linking landscape evolution models to land use change scenarios, human induced land use changes and their effects on long-term erosion and landscape evolution can be quantiied. As mentioned, a major challenge in this study is how to deal with scale problems such as spatial heterogeneity of processes, non-linear behaviour of processes in time and space, threshold dependency, varying dominant processes and differing responses to disturbances. A multi-scale modelling framework will be developed to integrate landscape evolution and local, short-term erosion processes. With this framework, innovative, integrated and sustainable erosion control and prevention techniques can be developed, implemented and evaluated. These will focus on the human-induced part of erosion and we will assess their effects on natural processes. Hence the objectives of this project are: (1) to develop a multi-scale modelling framework where local short-term measurements are integrated in a long-term landscape scale framework; (2) to develop modelling tools to separate natural erosion rates and processes from humaninduced erosion; (3) to assess the effects of the coupled land use landscape system in order to assess changes in erosion risk and (4) to develop trade-off curves and other decision support tools to evaluate measures that can prevent or control increased human-induced erosion. Two study sites are selected for the purpose of this study. One is in the Mediterranean area (Southern Spain; Guadalentin Basin, near Murcia), the other in Central America (Mexico; Cointzio Catchment, Michoacán State). In Spain, multidisciplinary research is ongoing and has been quite extensive. In this way, data and experience are readily available. The Mexican site is, on the other hand, little studied but the area is characterized by extensive erosion problems. From experience in Spain, research will be set-up in Mexico. Both sites are hotspots of the recently started international EU-project DESIRE (contract no. 037046), in which the present PhDresearch is embedded. This research will lead to increased insight into landscape functioning such as feedback mechanisms and self-regulation. Also, improvement in modelling-related scale problems is expected. For (local) society this research will result in the development of innovative, integrated and sustainable erosion control and prevention techniques by focussing on the human-induced part of erosion, evaluating the effects of historical measures and involvement of local stakeholders.